Loading and Unloading Units and Methods for Sheet Metal Processing

ABSTRACT

A loading and unloading unit for sheet metal providing a first tool holder is provided. Therewith, sheet metal processing tools may be passed from a first tool magazine that is attached to a fixed unit of the loading and unloading unit to a second tool holder integrated in a sheet metal processing machine or to a tool fixture of the sheet metal processing machine, and, thus, the number of tools automatically exchangeable in the sheet metal processing machine can be increased to create a more efficient and space-saving manufacturing process.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of, and claims priority under 35U.S.C. §120 to, PCT Application No. PCT/EP2009/009253, filed on Dec. 23,2009, which claimed priority to European Patent Application No. EP08022326.6, filed on Dec. 22, 2008. The contents of both of thesepriority applications are hereby incorporated by reference in theirentirety.

TECHNICAL FIELD

The invention relates to loading and unloading units and methods forsheet metal processing.

BACKGROUND

Many punching machines include an integrated magazine for storingpunching tools used for executing certain machining steps duringproduction of sheet metal parts. During production of sheet metal parts,which typically includes many different machining steps (e.g. punchingdifferent shapes, nibbling, thread forming), a large number of differenttools are necessary. The storing capacity of tool magazines that areintegrated in punching machines is often insufficient to support themany tools used to execute different machining steps.

There are different possibilities for providing a larger number of toolsthan that which may be accommodated in conventional tool magazines thatare integrated in punching machines.

In some cases, tools can be exchanged manually (e.g., by an operator) inthe tool magazine during breaks in machining processes. However, suchmanual methods can cause interruptions in the machining process andschedule, and also require manual effort. Therefore, such methods aregenerally inefficient.

Another alternative is to include a separate tool magazine in whichpunching tools are stored so that the punching tools can beautomatically exchanged in the tool magazine that is integrated in thepunching machine and picked up from the tool holders to be used formachining. However, such an alternative requires additional componentsof the punching machine and such components correlate to additionalcosts and enlarged space requirements of the punching machine. Moreover,due to the substantially high number of different machining steps that agiven punching machine can be expected to execute during use, thepossible number of tools to be stored is often insufficient to ensure anadequate economic production even when a separate standard tool magazineis used.

Also, in other types of sheet metal processing machines, namely bendingmachines, an automatic exchange of the tools is possible. The bendingtools are also stored in a tool magazine in the bending machine and theyare automatically moved to a position to be used in a bending station.However, due to the large dimensions of the bending tools, the costassociated with the bending tools in or at the machine can be moreexpensive than that of punching tools.

Further types of sheet metal processing machines in which an automatictool exchange can be used include combination machines that combinemultiple processing capabilities. Examples of such combination machinesinclude punching/bending machines and punching/laser machines.

SUMMARY

In some aspects of the invention, a handling system is provided whichautomatically exchanges tools within a sheet metal processing machinewithout creating considerable additional space requirements or requiringsubstantially larger capital expenditures to be used.

In some aspects of the invention, a handling system is provided thatallows a sheet metal processing device to use the same assemblies foraccomplishing different tasks (e.g., to use a sheet metal workpieceloading and unloading unit as a tool handling system).

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 a shows a side view of a loading and unloading unit for a sheetmetal workpiece with a tool magazine for punching and forming tools;

FIG. 1 b shows an enlarged plan view of a rotatable holder with two toolholders;

FIG. 1 c is a schematic side view of a sheet metal picking unit with atool holder gripping a bending tool positioned in a tool holder;

FIG. 2 is a perspective view of a punching machine;

FIG. 3 is a perspective view of a bending machine;

FIGS. 4 a through 4 c illustrate tool exchange procedure for a bendingmachine.

DETAILED DESCRIPTION

FIG. 1 a is a side view of a loading and unloading unit 1 of a sheetmetal processing machine. The loading and unloading unit 1 includes afixed unit 2. The fixed unit 2 includes a frame with two vertical stands3 and a horizontal linear unit 4. At a movable portion of the horizontallinear unit 4, a vertical linear unit 5 is provided which is movable ina vertical direction. At its lower end, the vertical linear unit 5includes a sheet metal picking unit 6. The sheet metal picking unit 6includes devices (e.g., gripping fingers, vacuum nozzles, and/ormagnets) for picking up sheet metal plates.

A drive 7 (e.g., an electric motor or actuator) is included in thevertical linear unit 5 for moving the vertical linear unit 5 with thesheet metal picking unit 6 in a first horizontal direction along thehorizontal linear unit 5 (X-direction) and for moving in a secondhorizontal direction (Y-direction). A drive 8 is also included formoving the sheet metal picking unit 6 in a vertical direction.

Alternatively, one single drive can be included to provide all motioncapabilities of the drive 7 and the drive 8.

A rotatable holder 9 is provided on the upper side of the sheet metalpicking unit 6. The rotatable holder 9 includes two first tool holders10 for holding tools 11 used for sheet metal processing (e.g., punchingtools). The holder 9 is attached to the sheet metal picking unit 6 sothat it is rotatable about a vertical axis 12. As shown in FIG. 1 b,when viewed in the direction of the axis 12 (e.g., from the top or thebottom), the tool holders 10 are positioned 90° from each other.However, in some embodiments, the tool holders 10 are positioned atdifferent angles (e.g., 180°) from each other.

In some embodiments, the rotatable holder 9 includes only one toolholder 10. In other embodiments, multiple tool holders 10 are positionedside by side in the X-direction along the sheet metal picking unit 6. Insome embodiments, more than two tool holders 10 are included and arearranged around the axis 12 in a revolver-like manner. In someembodiments, in addition to a rotating around the axis 12, the rotatableholder 9 translates in the Y-direction and/or the first tool holders 10translate radially relative to the rotatable holder 9. Also, in someembodiments, tool holders 10 provided side by side at the tool pickingunit 6 can translate in the Y-direction.

Opening and closing movements of the first tool holders 10 to grip tools11 are typically driven and controlled pneumatically. The rotarymovement of the rotatable holder 9 is also typically driven andcontrolled pneumatically, by a pneumatic rotary drive. Alternatively, insome embodiments, the movements of the tool holders 10 and the rotatableholder 9 are driven and controlled by an electrical drive (e.g. astepping motor). Such an arrangement can be beneficial when more thantwo first tool holders 10 are positioned at the rotatable holder 9.

In some embodiments, an interface is provided so that the additionalweight due to moving the tool holders 10 which are held on the sheetmetal picking unit 6 is not always transported during use. Thisinterface can be the joint between the sheet metal picking unit 6 andone of the tool holders 10 or the rotatable holder 9 on which the toolholders 10 are arranged. In some embodiments, multiple interfaces areprovided. The interfaces can also be movable in the Y-direction, ormovement can be performed by a tool holder fixed to the interface or bythe rotatable holder.

The rotatable holder 9 or the tool holder 10 is fixed at the interfaceby a magnetic force, a form-fit attachment, or other appropriatetechniques.

A first tool magazine 13 for punching tools is provided between the twovertical stands 3. Multiple (e.g., six in the illustrated embodiment)second tool holders 14 for punching tools are included in the toolmagazine 13, which are horizontally arranged side by side in theX-direction. As shown in FIG. 1 a, punching tools 11 are held in thesecond tool holders 14.

In order to provide multiple second tool holders 14, in someembodiments, the tool magazine 13 includes the second tool holders 14arranged along several horizontal planes. Alternatively, in someembodiments, the second tool holders 14 are arranged along onehorizontal plane and positioned consecutively in the Y-direction. Also,in some embodiments, the second tool holders 14 are arranged side byside in X-direction and Y-direction.

When used with bending machines, second tool holders 14 suitable forreceiving and supporting bending tools are provided, which are alsoarranged between the two vertical stands 3. In some embodiments, thefirst tool magazine 13 for punching tools or the first tool magazine 13for the bending tools is not integrated in the fixed unit 2. In suchembodiments, the first tool magazine 13 is a separate component of themachine and is arranged in or near the field of motion of the sheetmetal picking unit 6.

In some embodiments, the first tool magazine 13 is positioned on thesheet picking unit 6.

As shown in FIG. 1 a, a second tool magazine 15 is also included, whichwill be explained in greater detail below with regards to FIG. 2.

FIG. 1 c shows a schematic side view of a sheet metal picking unit 6with a fourth tool holder (e.g., a vacuum nozzle) 39 arranged on thelower side of the sheet metal picking unit 6. The first tool magazine 13with the second tool holders 14 and bending tools 11 positioned in thetool holders 14 are also shown in FIG. 1 c. In some embodiments,multiple fourth tool holders 39 are included on the sheet metal pickingunit 6. The fourth tool holders 39, while described as vacuum nozzles,can alternatively or additionally be gripping fingers and/or magnets.During use, these multiple fourth tool holders 39 can be used forpicking up sheet-metal plates as well as for picking up tools designedin a suitable manner. When using vacuum nozzles or magnets as toolholders, it has been found favorable to use tools having at least onelarger flat portion to allow for proper engagement with the tool holder.Including larger flat portions on tools can be especially beneficialwhen bending tools 11 are used.

FIG. 2 shows a sheet metal processing machine in the form of a punchingmachine 21 that is used with or includes the loading and unloading unit1. The punching machine 21 includes a C-frame 22 that consists of atorsionally stiff, steel-welded construction. At a rear region of theC-frame 22, a hydraulic power unit 23 is positioned, by which a ram 25is hydraulically driven by a ram drive.

At the lower inside region of the C-frame 22, a lower tool fixture 24 ispositioned for receiving and holding a lower part of a punching tool 11.The lower part of the tool is rotatable up to 360° using a rotary driveand can be locked and fixed at any desired angular position.

At the upper inside region of the C-frame 22, a ram 25 is provided. Theram 25 includes an upper tool fixture to receive and hold an upper partof a punching tool 11 in a form-fit and backlash-free manner. The ram 25is also rotatable up to 360° and can be locked in any desired angularposition. To provide rotation to the ram 25, a second rotary drive isprovided.

The rotary drives as well as the driving devices 7, 8 of the loading andunloading unit 1 are controlled by a machine controller, which isprovided in a separate control cabinet. The machine controller alsocontrols a ram controller as well as all of the linear drives for movinga sheet metal plate 26 and actuators for special functions (e.g., tomove the part flap 27 up and down). The machine controller includes akeyboard to enable a user to input information and a monitor that canoutput data to be viewed by the user. The control functions of thedrives and actuators are controlled by microprocessors, and machiningprograms and operation parameters are stored electronically in a storagedevice of the machine controller.

At the lower inside region of the C-frame 22, a table 28 is arrangedthat includes a cross rail 29 with a linear magazine (i.e., the secondtool magazine 25). Clamping claws 30 for retaining the sheet-metal plate26 are arranged along the cross rail 29. The clamping claws 30 can bearranged at, or relocated to, suitable locations along the cross rail 29so that the sheet metal plate 26 is safely retained but is not grippedat positions where machining shall be conducted. Multiple (e.g., threein the illustrated embodiment) third tool holders 31 for receivingmultiple (e.g., two in the illustrated embodiment) punching tools 11 areincluded along the linear magazine 15. In front of the lower toolfixture 24, the part flap 27 is arranged centrally for transferringoutward smaller sheet metal parts.

During punching operations, the table 28 travels along a programmedrange of positions in the Y-direction together with the cross rail 29 onwhich the clamping claws 30 are arranged to hold the sheet metal plate26. The cross rail 29, along with the clamping claws 30 and sheet metalplate 26, travels along a programmed range of positions in X-direction,whereby the sheet metal plate 26 slides over the table 28. Then, withthe sheet metal plate 26 in a desired position, a punching stroke isperformed by the ram 25. Subsequently, the sheet metal plate 26 is movedto the next punching position and a subsequent punching stroke can beperformed.

During use, the punching tools 11 are automatically exchanged based onthe punching operation to be executed, such exchange being controlled bythe machine controller. For exchanging the tools 11 from the second toolmagazine 15, the cross rail 29 is driven by a linear drive along theX-direction so that the position of the tool 11 to be exchanged in theX-direction corresponds to the position of the lower tool fixture 24 inthe X-direction. Then, the cross rail 29 travels together with the table28 in the Y-direction so that a central axis of the punching tool 11 isaligned with a central axis of the lower tool fixture 24 and the ram 25,so that the punching tool 11 can be held in the lower tool fixture 24and in the ram 25. If a tool is positioned in the ram 25 and in thelower tool fixture 24, this tool is dispensed to a free space in thelinear magazine 15 before the next tool is brought to the ram 25 and thelower tool holder 24.

For exchanging a tool 11 from the first tool magazine 13 with a tool inthe upper tool fixture 25 and the lower tool fixture 24, first, thenecessary punching tool 11 is taken from the first tool magazine 13. Thesheet metal picking unit 6 travels in the X-direction such that the axis12 of the rotatable holder 9 is aligned with a central axis 17 of thedesired punching tool 11. Subsequently, the sheet metal picking unit 6travels in the Y-direction so far backwards that the first tool holder10 may grip the punching tool 11 (i.e., an orifice 16 (referring to FIG.1 a) of the first tool holder 10 can grip the punching tool 11 in aform-fit manner). Then, a closing movement of the first tool holder 10is performed and the punching tool 11 is removed from the second toolholder 14 of the first tool magazine 13 of the sheet-metal picking unit6 and moved in the opposite Y-direction by a forward movement. Then, thesheet-metal picking unit 6 travels in X-direction until the central axis17 of the punching tool is aligned with the central axis of the uppertool fixture 25 and lower tool fixture 24 and, subsequently, thesheet-metal picking unit 6 analogously travels in the Y-direction.Thereafter, the punching tool 11 is received and retained by the toolfixtures 24, 25 in a conventional manner. When used in this manner, itis necessary that a free space is available in front of the lower toolfixture 24 because the movement for exchanging tools is typicallyhorizontal. For creating the free space in front of the lower toolfixture 24, the part flap 27 is moved downward vertically. However, tohinge the part flap 27 to move only downward is insufficient because inthis case, the hinge axis of the part flap 27 remains unchanged in theregion of collision with the tools to be exchanged in the tool fixtures24, 25.

As an alternative to moving the sheet metal picking unit 6 in theY-direction, in some embodiments, only the first tool holder 10 or therotary holder 9 travels in Y-direction.

The first tool holder 10 is typically moved in the Y-direction, however,the movement of the first tool holder 10 is selected such that it movesin relation to the second tool holder 14 so that the punching tool 11can be taken out of the second tool holder 14 or the punching tool 11can be delivered to the second tool holder 14.

In addition to the respective described methods for changing punchingtools 11 of the first tool magazine 13 and the second tool magazine 15in and out of the tool fixtures 24, 25, other methods for exchanging thepunching tools 11 are possible.

In some embodiments, the punching tool 11 to be exchanged in the secondtool magazine 15 is removed from the first tool magazine 13 by one ofthe first tool holders 10 and then passed to a third tool holder 31 inthe second tool magazine 15 in the same manner that a punching tool 11is placed in the upper tool fixture 25 and the lower tool fixture 24.When a punching tool 11 is already present in the third tool holder 31in which the punching tool 11 is to be placed from the first tool holder10, the rotatable holder 9 is rotated approximately 90° or the sheetmetal picking unit 6 is moved in the X-direction such that another ofthe first tool holders 10 is positioned to remove the punching tool 11present in this third tool holder 31. Subsequently, the rotatable holder9 is rotated in the opposite direction, here approximately 90°, or thesheet metal picking unit 6 is moved in the opposite X-direction in orderto pass the punching tool 11 to be exchanged to this third tool holder31. The punching tool 11 that was removed from the second tool magazine15 can then be either moved to the first tool magazine 13 or it can beinserted in the upper tool fixture 25 and the lower tool fixture 24.

Using similar techniques, the punching tools 11 may be removed from thesecond tool magazine 15 and moved directly to the first tool magazine13.

In some embodiments, in which two or more of the first tool holders 10are arranged side by side on the sheet metal picking unit 6, multiplepunching tools 11 can be removed from the first tool magazine 13 andmoved to the second tool magazine 15 (or removed from the second toolmagazine 15 and moved to the first tool magazine 13) at the same time.

Further, depending on the number of the first tool holders 10 arrangedside by side on the sheet metal picking unit 6 or the number of the toolholders included on the rotatable holder 9, several punching tools 11may be used and positioned in other first tool holders 10.

The method for exchanging the punching tools from the first toolmagazine 13 may be executed along with the loading the punching machine21 with a sheet metal plate (i.e., the punching machine can load a sheetmetal plate and the desired punching tools at the same time). In thismanner, first, the desired punching tools 11 are taken from the firsttool magazine 13, then, the sheet metal plate 26 is removed from amagazine in the region of the fixed unit 2 by gripping devices or vacuumnozzles and the obtained punching tools 11 are moved to the punchingmachine along with the sheet metal plate 26. Then, the punching tools 11are placed in either the second tool magazine 15 or the upper toolfixture 25 and lower tool fixture 24. The sheet metal plate 26 is placedon the table 28 and moved to a position to be retained by the clampingclaws 30. The unloading of manufactured sheet metal parts may also beexecuted along with the exchange of punching tools 11 in the first toolmagazine 13.

FIG. 3 shows a bending machine 33 having a basic structure that issimilar to that of the punching machine 21 shown in FIG. 2 and describedabove. The bending machine 33 includes an upper tool fixture 34 with adrive 36 and a lower tool fixture 35 as well as a controller. Somemachine components (e.g. the tool fixtures 34, 35 and the driving device36) are optimized for the bending process using bending tools. As shownin FIG. 3, sheet metal 26 is furnished with cut outs 37 which are bentupward using the bending machine to form upwardly bent sheet metalportions 38.

The exchanging of additional sheet metal processing tools 11 (e.g.,bending tools) from the first tool magazine 13 to the bending machine orout of the bending machine to the first tool magazine 13 may also occurdirectly in the second tool magazine of the bending machine or directlyin the tool fixtures 34, 35.

In FIGS. 4 a to 4 c, the upper tool fixture 34 and the lower toolfixture 35 for bending tools 11 and the sheet metal picking unit 6 withthe fourth tool holder 39 (from FIG. 1 b) are respectively shown. Thebending tools 11 respectively include a lower part (e.g., a1, b1) and anupper part (e.g., a2, b2).

A method of exchanging the bending tools out of, and into, the toolfixtures 34, 35 is described below.

As shown in FIG. 4 a, a bending tool with a lower part a1 and an upperpart a2 is accommodated in the tool fixtures 34, 35. To begin removingthe bending tool, the sheet metal picking unit 6 travels toward the toolholders 34, 35 so that the fourth tool holder 39 is located above thelower part al, the fourth holder 39 attaches to the lower part of thetool a1 (shown in view I), the lower part a1 is loosened or releasedfrom the lower tool fixture 35, and the fourth holder 39 removes thelower part of the tool a1 out of the lower tool fixture 35 (shown inview II).

With the lower part of the tool a1 removed from the lower tool fixture35, a lower part b1 is inserted in the lower tool fixture 35 using thefourth holder 39 (shown in view III). Once the lower part b1 is insertedin the lower tool fixture 35, the lower part b1 is fixed or fastened inplace in the lower tool fixture 35.

As shown in FIG. 4 b, the upper tool fixture 34 having the upper part ofthe tool a2 is moved downward to contact the lower part b1, which ispositioned in the lower tool fixture 35. Once in contact with the lowerpart b1, the upper part of the tool a2 is loosened or released from theupper tool fixture 34 so that when the upper tool fixture 34 movesupward and away from the lower tool fixture 35, the upper part of thetool a2 remains positioned on the lower part of the tool b1 (shown inview IV).

Then, the sheet metal picking unit 6 travels so that the fourth toolholder 39 is located above the upper part of the tool a2, which ispositioned on the lower part of the tool a1 picks up the upper part ofthe tool a2 (shown in view V).

With the upper part of the tool a2 removed from of the machine (shown inview VI), the upper part of the tool b2 can be moved toward the toolfixture 35 and placed on top of the lower part of the tool b1 by thesheet metal picking unit 6 and the fourth tool holder 39 (shown in viewVII of FIG. 4 c).

To complete the exchange of the bending tool, the upper tool fixture 34travels downwards and picks up the upper part of the tool b2 (shown inview VIII). Once the upper tool fixture 34 receives the upper part ofthe tool b2, the upper tool fixture 34 retains the upper part of thetool b2 and moves back upward (shown in view IX).

In some cases, the removal of tools from the first tool magazine or theplacement of tools into the first tool magazine can be executed inparallel to the production of sheet metal parts. Therefore, while sheetmetal is machined in the sheet metal processing machine, a tool can beremoved from the first tool magazine or placed in the first toolmagazine by the loading and unloading unit 1 for sheet metal workpieceswithout considerable disturbance of the machining procedure (e.g.,punching or bending of the sheet metal).

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Accordingly, other embodiments are within the scope of the followingclaims.

1. A loading and unloading unit for a sheet metal processing machine, the loading and unloading unit comprising: a fixed unit; and a sheet metal picking unit comprising: at least one device configured to pick up sheet metal; at least one driving device for moving the sheet metal picking unit in at least one horizontal axis; and at least one first tool holder for holding a sheet metal processing tool.
 2. The loading and unloading unit according to claim 1, wherein the fixed unit comprises a first tool magazine with at least one second tool holder.
 3. The loading and unloading unit according to claim 1, wherein the sheet metal picking unit comprises at least two first tool holders.
 4. The loading and unloading unit according to claim 1, wherein the at least one first tool holder can move in relation to the sheet metal picking unit.
 5. The loading and unloading unit according to claim 4, wherein the loading and unloading unit comprises a plurality of first tool holders that are fixedly positioned in relation to each other.
 6. The loading and unloading unit according to claim 4, wherein the loading and unloading unit comprises a plurality of first tool holders that can rotate relative to the sheet metal picking unit.
 7. The loading and unloading unit according to claim 1, wherein the sheet metal processing tool is a punching tool.
 8. The loading and unloading unit according to claim 1, wherein the sheet metal processing tool is a bending tool.
 9. A sheet metal processing machine comprising: a loading and unloading unit comprising: a fixed unit; and a sheet metal picking unit comprising: at least one device configured to pick up sheet metal; at least one driving device for moving the sheet metal picking unit in at least one horizontal axis; and at least one first tool holder for holding a sheet metal processing tool; and a controller configured to control the at least one driving device to move the sheet metal picking unit.
 10. The sheet metal processing machine according to claim 9, wherein the processing machine is a punching machine that comprises an upper tool fixture and a lower tool fixture.
 11. The sheet metal processing machine according to claim 9, wherein the processing machine is a bending machine that comprises an upper tool fixture and a lower tool fixture.
 12. The sheet metal processing machine according to claim 9, wherein the controller is adapted to output signals to the at least one driving device such that at least one sheet metal processing tool is passed from a first tool magazine attached to the fixed unit to a second tool magazine of the sheet metal processing machine or to a tool fixture of the sheet metal processing machine.
 13. The sheet metal processing machine according to claim 9, wherein the controller is adapted to output signals to at the least one driving device such that the sheet metal processing tool can be taken from the second tool magazine of the sheet metal processing machine or from a tool fixture of the sheet metal processing machine.
 14. A sheet metal processing tool exchange method, the method comprising: using a loading and unloading unit of a sheet metal processing machine as a tool holder of the sheet metal processing machine to move a sheet metal processing tool from a first tool magazine that is attached to a fixed unit of the loading and unloading unit to a second tool magazine of the sheet metal processing machine.
 15. The method according to claim 14, further comprising using the loading and unloading unit of the sheet metal processing machine as a tool holder of the sheet metal processing machine to move the sheet metal processing tool from the second tool magazine of the sheet metal processing machine to the first tool magazine attached to the fixed unit.
 16. The method according to claim 14, wherein moving the sheet metal processing tool occurs while a sheet metal plate is loaded into the sheet metal processing machine or while a manufactured sheet metal part is unloaded from the sheet metal processing machine.
 17. The method according to claim 14, wherein the sheet metal processing tool is moved from the first tool magazine while a sheet metal plate is machined in the sheet metal processing machine.
 18. The method according to claim 14, wherein the sheet metal processing tool is moved to the first tool magazine while a sheet metal plate is machined in the sheet metal processing machine.
 19. A sheet metal processing tool exchange method, the method comprising: using a loading and unloading unit of a sheet metal processing machine as a tool holder of the sheet metal processing machine to move a sheet metal processing tool from a first tool magazine that is attached to a fixed unit of the loading and unloading unit to a tool fixture of the sheet metal processing machine; and removing the sheet metal processing tool from the tool fixture of the sheet metal processing machine.
 20. The method according to claim 19, further comprising using a sheet metal picking unit of the loading and unloading unit to replace a sheet metal processing tool comprising a lower part and an upper part, the lower part of the sheet metal processing tool being disposed in a lower part of the tool fixture and the upper part of the sheet metal processing tool being disposed in a upper part of the tool fixture, wherein the upper part of the tool fixture moves relative to the lower part of the tool fixture to release the upper part of the sheet metal processing tool and place the upper part of the sheet metal processing tool on the lower part of the sheet metal processing tool so that it can be picked up by the sheet metal picking unit in a subsequent step.
 21. The method according to claim 19, further comprising using a sheet metal picking unit of the loading and unloading unit to replace a sheet metal processing tool comprising a lower part and an upper part, the lower part of the sheet metal processing tool being disposed in a lower part of the tool fixture and the upper part of the sheet metal processing tool being configured to be received in an upper part of the tool fixture, wherein the upper part of the sheet metal processing tool is placed on the lower part of the sheet metal processing tool that is disposed in the lower part of the tool fixture using the sheet metal picking unit, the upper part of the sheet metal processing tool being retained by the upper tool holder in a subsequent step. 